Add support for removing more testing binaries to reduce space
requirements for testers. This adds a new "--remove-test-targets" option
to enable the extra removals.
Add support for MSVC 14
adjust paths to modular layout
make qt5 rcc testcase use Qt5Core
Add support for Qt builds using bundled ANGLE
Add testing.execution feature.
Specify linker flags in clang.jam like gcc.jam, close #5820

  This is not clang's defect, however in most cases expects GNU ld as a
  backend linker.

  1. Use --{start,end}-group to avoid object linking order probrem.
  2. Use -Wl,-B{static,dynamic} to treat static library correctly.

  see also: https://svn.boost.org/trac/boost/ticket/5820
Merge pull request #15 from MarcelRaad/develop

Add support for MSVC 14
Merge 'boostorg/develop' into develop

Signed-off-by: Kohei Takahashi <flast@flast.jp>