moved everything into /trunk/ to create the standard svn layout, for use with tools that require this (eg. git-svn). IMPORTANT: do NOT do an `svn up`. instead, re-use your working copy's existing files with `svn switch` (http://svnbook.red-bean.com/en/1.6/svn.ref.svn.c.switch.html).

lib/mappings.Makefile: Checking if $(termsSubdirs) defined: Fixed bug where can't use ifndef because that checks if the variable is empty, not undefined. Need to use `ifeq ($(origin var),undefined)` instead.

lib/mappings.Makefile: unmapped_terms.csv, new_terms.csv: Only remake if newer than existing %/unmapped_terms.csv, %/new_terms.csv which haven't been autoremoved. This avoids always remaking every unmapped_terms.csv, new_terms.csv whenever `make missing_mappings` is run. Note that these files will automatically be remade whenever their corresponding map.csv changes, so it is not necessary to actually remake %/unmapped_terms.csv, %/new_terms.csv; they are prerequisites only so that their modification time may be checked to determine whether unmapped_terms.csv, new_terms.csv needs to be remade.

lib/mappings.Makefile: missing_mappings: Display unmapped_terms.csv, new_terms.csv after generating them, to preserve the behavior of the original missing_mappings

lib/mappings.Makefile: Removed no longer needed missing_%_mappings targets, since unmapped_terms.csv and new_terms.csv now serve the same purpose in a more efficient way

lib/mappings.Makefile: `ifndef` for $(termsSubdirs): Fixed bug where needed to be termsSubdirs instead of missingMappingsCmd

lib/mappings.Makefile: Require $(termsSubdirs)

lib/mappings.Makefile: $(catTerms): Fixed bug where only existing $+ files (using $(+w)) could be included in the list (both to check and to use), because otherwise cat would raise an error or try to read stdin

lib/mappings.Makefile: Added unmapped_terms.csv, new_terms.csv which are generated by combining the correspondingly-named files in $(termsSubdirs)

root Makefile, input.Makefile: Maps validation: Treat missing join mappings differently from missing non-empty join mappings, because they indicate mapping to an invalid location, which is a bug. Factored maps validation code out into new lib/mappings.Makefile.