Print warning message when SC_BUILD_SCHEMAS is unset
libexpress is no longer a dependency of the class libs

great!
missed two macros during SCL_->SC_ rename
doxify a comment that looks important, also copied to sc wiki
add (commented out) ParseTrace function for lemon parser debugging
remove unused LISTcreate_with() macro

also removes even older function in an `#if 0` block
K&R declaration for LISTfree()
minor cleanup
silence two Wundef warnings
travis-ci: -j3 is slow, try -j2; pulls are checked, so skip review branches
Merge pull request #245 from stepcode/review/cleanup

Review/cleanup