qt: remove extraneous padding introduced in multiwallet support patch

solve issue #2529
Add Bitcoin-Qt.app to .gitignore

Saves you from seeing everything in the Bitcoin-Qt.app/Contents/ dir
after compiling
Merge pull request #2573 from fanquake/bitcoin-qt-app-gitignore

Add Bitcoin-Qt.app to .gitignore
Merge pull request #2572 from laanwj/2013_04_wasted_space

qt: remove extraneous padding introduced in multiwallet support patch