copied files from rosinstall
renamed imports to wstool module
disable warning message breaking tests (and being annoying anyway)
reduced helper functions for wstool
fix: ros in package path check obsolete for wstool (not rosinstall)
minor fix: default option prevents using e.g. --merge-replace
Translate tests to wstool
get rid of rosinstall Exception (kept in rosinstall)
wstool cmd_init is now default cmd_init. rosws has its own
Merge branch 'code_migration' of github.com:tkruse/wstool into tkruse-code_migration