Merge remote-tracking branch 'kiliman/master' (#185)

* OperatorMonoSSm (Light, Book, Medium, Bold)
New Ligatures:
    - colon_colon
    - exclam_exclam
    - semicolon_semicolon
    - less_less
    - greater_greater
    - hyphen_equal (minus_equal)
    - asterisk_equal
    - slash_equal
    - less_slash_greater
    - less_less_equal
    - quotedbl_quotedbl_quotedbl
    - quotesingle_quotesingle_quotesingle
New Powerline Glyhps:
    - E0A1 (Powerline LN)
    - E0A2 (Powerline lock)
    - E0B1 (Powerline left soft divider)
    - E0B3 (Powerline right soft divider)

Features:
    - ss10 can be used to substitute 'x' for '×'. Eg 0×FF or 800×600
    - 'Equality Spaces' and 'Less-than/Greater-than Horizontal Bar' alternatives are included
    by default, and can be activated via ss11 and ss12 respectively.
    - Corrected and simplified features code to include the missing 'kern' feature for
    fraction numerator and denominator positioning.
    - 'calt.js' will also generate the 'liga' feature.

Edited and repositioned some existing glyphs to be more consistent across font weights.
Created missing glyphs for other weights. Eg 'w_w_w.liga' and 'plus_equal.liga'

* 'calt.js' no longer generates the 'liga' feature.

* Adjusted hinting, no contours changed.

ligature/OperatorMonoSSmLig-Bold/glyphs/hyphen_hyphen.liga.xml

@@ -1,10 +1,9 @@
-<Glyph name="hyphen_hyphen.liga" lsb="-415" width="625">
+<Glyph name="hyphen_hyphen.liga" lsb="-429" width="625">
     <CharString>
         269 134 hstem
-        -415 361 108 361 vstem
-        -54 403 rmoveto
+        437 403 rmoveto
         -361 -134 347 hlineto
-        483 134 rmoveto
+        -491 134 rmoveto
         -361 -134 347 hlineto
         endchar
     </CharString>