chg: added brackets around floating numbers

fixed latex lib and updated res files

for long coefficients.tst, note that
286391521141683198701331939250003266767738632875
/12103947791971846719838321886393392913750065060875
=0.02366...

and not

=24.12...

which was the previous result.
fix: missing sign when converting number to float
Merge pull request #303 from YueRen/floatprint

chg: added brackets around floating numbers
fix: work around abort() in allowed int overflow