Merge pull request #116 from chrox/master

clean up punctuation patch and fix floating CJK punctuation
Update sdcv (&apos; support)
Merge pull request #117 from thotypous/master

Update sdcv (&apos; support)
Merge pull request #118 from chrox/master

fix punctuation width calculation
Merge pull request #119 from chrox/master

fix an infinite loop when upskip a left punctuation
fix for PAM files when writing RGB, conversion RGB16->24/32

PAM writing for all RGB formats was broken (wrong max value of 256, it is in fact 255).

Also, conversion from RGB16 to RGB24 or RGB32 was also wrong due to a typo.
Merge pull request #120 from hwhw/fix-screenshot

fix for PAM files when writing RGB, conversion RGB16->24/32
add go back/forward method for credocument