basic diphthong support achieved
implemented arrows
documentation related to diphthongs
documentation updates
documentation fixes
new implementation of poly.order (eliminates need for poly.include)
reverting accidental ahead-of-schedule changes to the polygon error handling logic.
bugfixes in prep for CRAN
minor bugfix in error handling
Merge branch 'fixPolyOrder'

Conflicts:
	phonR/R/phonR.r