science/chemtool: Update 1.6.11 -> 1.6.14

Port changes:

• Take maintainership
• Change to DISTVERSION
• Add LICENSE/LICENSE_FILE
• Add missing dependencies in LIB_DEPENDS and USE_GNOME
• Add the NLS option
• Add PORTEXAMPLES=*
• Remove post-patch (not needed)
• Remove do-install (not needed, except for EXAMPLES)