Minor changes to the solution file to make it compatible with VS10.

Weird behavior was observed during fwrite when files were only opened
with "a". fwrite did not write the expected number of bytes (probably
augumented things with a \n or \r). This caused serious problems parsing
the dumped files in matlab. Forcing a binary fopen option fixed things.

VS throws errors in several locations about ambigious type casting.
Fixed by removing the ambiguities and casting things to double.

Fixed spike detector crash

This fixes a segfault that happened when no electrode was selected on a spike detector (e.g., with no electrodes added); getSelectedItemIndex returns -1 in this case, which was causing an array bounds segfault in drawElectrodeButtons.