Release RP-1 Realistic Progression One v1.9 for KSP 1.8.1

Major Updates:

The midgame of RP-1 has been rebalanced to lower the snowball effect of the early and mid lunar missions. This involves changes to the tech tree, to contract parameters and rewards, and to parts.
KCT's codebase has seen a big refactor - the user facing improvements include descriptions for the various tags applied to parts and a KCT-friendly Engineer's Report.
RP-1 has been updated to support the latest changes in RO v13.1. Chief among these is a change to heating, and so there have been changes to the heatshields in RP-1 (more reordering and changes are to come). In particular the Sample Return Capsule now uses a heatsink-style heat shield (i.e. it does not come with ablator), and so reentries using it must be very carefully done. Make sure to provide a substantial retro fire (200m/s or more), and come from a very low orbit.

Avionics units no longer stack. This means that to control a rocket of 20 tons, at least one avionics unit must have a controllable mass of 20+ tons. Note that you can still have separate lower and upper stage avionics, they just don't combine their controllable masses. This feature defaults to off in existing saves, and is toggleable in the RP-1 difficulty settings.
Add a setting in RP-1's difficulty settings to allow toggling whether the Procedural Avionics GUI opens automatically when right-clicking a part in the editor
Add Range Safety functionality to all parts with Procedural Avionics
Warn when trying to close the Proc Avionics window if the avionics type has not been applied

Improvements and bugfixes to sim functionality. Should fix a random crash with Principia on reverts.
Fix crew selection dialog for vessels with multiple different crewable parts
KCT now overrides the Engineer's Report applauncher, so that it displays the actual mass and size of the vessel
Part tags now have individual descriptions that show in the editor part tooltip
Large refactor of the KCT codebase for stability and performance
Support the new tag PadInfrastructure so that parts from MLP can be ignored for mass/size checks even if they are not themselves launch clamps
Highlight Rollout button when rollout checks fail (#1513)

Add a tab to the RP-1 GUI that allows setting allowable satellite contract payload limits
Improvements to the SCANSat contracts
Go back to gating First Docking behind unlocking docking ports (#1475)
No longer prevent having both Suborbital Crewed and First Crewed Orbital active
Fix some issues with the lunar impactor contract not completing
Break the Sound Barrier contract now depends on the Mach value, not a hardcoded 343m/s
Enable all space station contracts rather than only one per station (#1511)
Reduce midgame contract payouts (#1418)
Alter lunar contract requirements to lower midgame snowball effect (#1472)
Add new far side lunar landing contract
Slight increase to early satellite contract rewards
Add shared soft cooldown to all repeatable satellite contracts
Make First Solar-Powered Satellite contract require positive electricity balance (Note: a Contract Configurator bug requires switching away from and back to the vessel before the contract will complete)

Move Hydrazine (RCS/generic engine propellant) to 1968, since that was the first time it was used in an infinite-ignition setting
Add ScanSat biome scan to cameras (#1467)
Improve kOS tech progression, now follows selected avionics tech level (#1498)
Phobos and Deimos now have only a single biome each, and only have low-space science (#1505)
Lower cost of all '58-'61 tech nodes
Lower landed multipliers on the Moon

Support reDIRECT
Add tech progression for the ORM-65 engine (#1468)
Unlock the first tank configs from the start (#1469)
Support new small thrusters from RO (#1463)
Support new X-1 cockpit from RO
Interstages, decouplers, and fairing bases no longer require tooling. Fairing side tooling is more expensive now however.
Add small radial sep motor (#1482)
Support ROCapsules Apollo Block III Service Module (#1478)
Fix the LR87-LH2 ECMs
Improve ECM handling for the AJ10-Advanced and the AJ10-133
Set resource costs of solids to 0 to avoid a resource cost issue when partially loading propellant
Clean up station part prices and ECMs
Support GE Apollo D-2 from ROCapsules
Support ROEngines SNTP
Fix Zond avionics
Moved the Gamma 201/301 back a node in the tech tree

Fix issues with training course generation. Use part title instead of name for unconfigured parts.
Add a new difficulty option for crew training that disables mission training but keeps proficiency training
Increase the craft size limits for launch pads
Fix CommNet being disabled on the Easy difficulty preset
Alter hypoxia behavior so it becomes more dangerous as altitude increases and density decreases, and as time above the limit increases. Ducking above a cockpit's altitude limit is much more dangerous now!