changed input edit: can have 2048 characters now
fixed: the focus (when using the tab key) didn't go from tabs into their controls
added: a button 'err' which shows us where is an error (an incorrect character etc.)
changed: diplaying an error message is from the main thread now
added: when the program calculates (for example the factorial) and an user clicks on the 'err' button
then a 'calculating...' message will be printed
git-svn-id: svn://ttmath.org/publicrep/ttcalc/trunk@14 e52654a7-88a9-db11-a3e9-0013d4bc506e