97 custom inspections

[RichardBradley]

This implements #97.

See corresponding changes in sbt-scapegoat.

(I haven't written any tests, as it's not very amenable to unit testing.)

[RichardBradley]

This is now working and tested -- see https://github.com/RichardBradley/scapegoat-custom-inspection-subproject-example

[RichardBradley]

(I can't repro that build failure. The tests all pass for me, on a linux box)

I can now -- it seems like the tests fail the first time they are run on a clean box (I don't think this is new though). I'm fixing.

I think it's scala 2.11.6 vs scala 2.11.7 somehow -- maybe a new release?

-- Yes, in commit 88c13b3 you changed scala version in build.sbt but not in PluginRunner. This will break the tests on the CI server or other machines without a cached copy of scala 2.11.6

[RichardBradley]

Actually, it might be safest to hold off merging this and scapegoat-scala/sbt-scapegoat#27 until I can do some more testing.

Some simple test projects which are included in this PR in src/sbt-test work fine, but I get weird class version incompatibility errors when I try to use this on a big real-world multi-module SBT project.

I'll update here when I have more info.

[RichardBradley]

Sorry that I haven't managed to finalise this. I haven't been using Scala for a couple of years.
The "big real-world multi-module SBT project" is finished.
I will re-open if I get a chance to tidy this up (but don't hold your breath).