add reconos_cleanup()
add Google Test library
add TAP listener library for Google Test

see https://github.com/kinow/gtest-tap-listener
https://github.com/kinow/gtest-tap-listener/commit/b0c1a440f9299f0cbc686ce8d6d00b705e33348d
install TAP header for Google Test
make gtestIncludePath and gtestLibPath file objects (instead of strings)
add Google Mock library
fix memory bug in tap.h

uncovered by valgrind: c_str() is used without storing a reference
to the string, i.e. the string is destroyed before the char* is used.
fix permissions of gtest and gmock headers

By default, the headers are not writable for anyone - not even for
the owning user. This means that Gradle fails to overwrite them
which makes the build fail. Therefore, we chmod existing headers
in the target directories before copying the headers.
ignore gmock build directory
Merge branch 'add-gtest'
Merge branch 'master' of github.com:BBBSnowball/mehari