The old type was [String] -> String. This function was only used
in GF.Text.Lexing.stringOp, which now uses (unwords . bindTok) instead,
with no change in behaviour.
The capitalization of the first word was done in GF.Text.Lexing.stringOp,
but is now done in the functions unlexText and unlexMixed in PGF.Lexing.
These functions are only used in stringOp and in PGFService (where the change
is needed), so the subtle change in behaviour should not cause any bugs.
Only change the first word to lowercase if the original input is not found in
the grammar's morphology. This allows parsing of sentenses starting with "I" in
English, nouns in German and proper names in other languages, but it can make
the wrong choice for multi-words.
