Changed int test to fail linking by using a duplicate symbol rather than a dodgy linker arg.
Some minor spec updates.
Fix the GCC assembler options on linux
Update test sample code to work on GCC on different platforms
REVIEW-3241: Split up / flesh out help related stories
Restructure Gradle cache layout to give file store and metadata separate versions.
REVIEW-3181: Moved class to core-impl project.
Simplified 'assembler' sample and fix it to work on all tool chains

- Now targets the i386 platform only
Establish the tool chain environment when testing C++ samples
More work to make the assembler sample work cross-platform and cross-toolchain
Cache layout version should be 29.
Extracted TestApp fixture out of HelloWorldApp.
Use compiler detecting app in c++ int test to verify the c++ compiler is being used.
Need to discard build script generated by superclass for this test.
Renamed compiler detecting test app.
Added CCompilerDetectingTestApp and use this to check that the c compiler is being used.
Changed TestApp so that it models the library and executable as separate TestComponents.
Removed some more convention mappings.
Removed Clang on cygwin as a supported tool chain (for now).
Mentioned some more nice features in the native languages support.