replace hyphen with unicode minus sign; unfortunately copying copies the minus sign, which is not valid maxima input
before send, minus is converted back to hyphen; minor consistency fix; closes #170
Merge branch 'master' into minus
cleaned up unused variables. closes #252. closes #251.
Merge pull request #256 from DemiReticent/codefix

cleaned up unused variables. closes #252. closes #251.
Merge pull request #249 from DemiReticent/minus

Issue 170: Use Unicode minus instead of hyphen in Unicode mode