Show backtrace on --trace

Change-Id: Ic778fc1c97a468b77f47e567bb9513ba841433b1
better variable names

Change-Id: I4426a63a4095d88f524ff4bc51aecc3d72ab0558
renamed source_library to static_library

Change-Id: I407fa0df7d08180038e7711e14f6d1994d93b75d
refactored output_ending in provider to be fitter for shared_libraries

Change-Id: Id18bde38acf7b0bb012ae1e9062a94d79778a9aa
renamed the class SourceLibrary to StaticLibrary

Change-Id: I5dd8aaee76f2d4b04193a83de11be9bad996b321
more work for shared libraries

Change-Id: I6c410054ad11a07f0ff358af14613bfb2c231aa5
renamed executable to linkable

Change-Id: I52d71c1e38fd646ce9fbcacdc07276afd4ecb849
deprecated warns each method only once

Change-Id: I830295d71912eedfe431db35894a381cd8baab79
more work on shared libs

Change-Id: I2fce10ff51da4ee59f3d0511de32dc3f49d1b6cb