mobile: API updates

[mniewrzal]

What: Changes for mobile API:

• expose SkipPeerCAWhitelist option in uplink config
• expose Scope type
• change default for bucket listing direction to storj.After
• update automatic tests to use scope instead apikey

Why: we need update gomobile API to build Java API facade

Please describe the tests:

• Test 1: automatic tests updated

Please describe the performance impact: none

Code Review Checklist (to be filled out by reviewer)

• Does the PR describe what changes are being made?
• Does the PR describe why the changes are being made?
• Does the code follow our style guide?
• Does the code follow our testing guide?
• Is the PR appropriately sized? (If it could be broken into smaller PRs it should be)
• Does the new code have enough tests? (every PR should have tests or justification otherwise. Bug-fix PRs especially)
• Does the new code have enough documentation that answers "how do I use it?" and "what does it do?"? (both source documentation and higher level, diagrams?)
• Does any documentation need updating?
• Do the database access patterns make sense?

[bryanchriswhite]

Am I understanding correctly that the purpose for the struct wrappers around things like Scope, APIKey, etc. is to be able to alter method definitions? If so, since we're now defining the high-level API in java, can we push that logic into java and just use the libuplink structs directly in the gomobile code (admittedly, that may be out of scope for this PR)? It's a bit confusing to follow structs of the same name defined in libuplink and then again in the gomobile code.

[bryanchriswhite]

Aside from my previous comment/question, this looks good!

[mniewrzal]

Am I understanding correctly that the purpose for the struct wrappers around things like Scope, APIKey, etc. is to be able to alter method definitions? If so, since we're now defining the high-level API in java, can we push that logic into java and just use the libuplink structs directly in the gomobile code (admittedly, that may be out of scope for this PR)? It's a bit confusing to follow structs of the same name defined in libuplink and then again in the gomobile code.

Purpose of mobile package is to adjust our libuplink code to code that can be used by gomobile to generate Java code. Gomobile have some limitation and this additional code is necessary even if we are doing manual Java API.
See https://godoc.org/golang.org/x/mobile/cmd/gobind#hdr-Type_restrictions

[egonelbre]

maybe let's change the cursor name here, to make it clear that it defaults to after. e.g. after string