Update README
Fix typo
Preliminary if condition handling

This is not really a boolean parser; it merely compares strings.
It should suffice to check for "if(CATKIN_ENABLE_TESTING)", at
least for now.
Handle test-only dependencies

Closes #17
Check test commands

All test commands have to be guarded by "if(CATKIN_ENABLE_TESTING)",
and the appriopriate test_depends have to be specified.
Remove unittest dependency for now
1.3.9
Merge version 1.3.9
Update build scripts
1.3.9-1