[merge] Improve assert
[merge] Rename
Make tag parameter to table constructor optional

If not provided, extract from class name.
[merge] Support missing GSUB/GPOS/etc

This is a hack for now.  Will clean up in upcoming commits.
Minor
[merge] Rename
[merge] Install merged dict on object
[merge] Allow merging OS/2 tables of different versions
[merge] Comment
[merge] Minor
[merge] Minor
[merge] Minor
Fix identifierToTag for Python 3
[merge] Minor
.
[merge] Map duplicate glyphs using synthesized GSUB 'locl' tables
[merge] Remove Python 2.7 dict comprehension syntax

Hopefully 2.6-happy again.
Allow disabling 'head' table modified-timestamp recalculation

Part of:
https://github.com/behdad/fonttools/issues/115
https://github.com/behdad/fonttools/issues/46
[subset] Don't recalculate "modified" timestamp

To recalculate (which was the default before), use --recalc-timestamp

Fixes https://github.com/behdad/fonttools/issues/115