Improve filesystembrowser

[supermihi]

• searchbox for filtering folder and/or file names
• filter by status (commited / not commited)
• show number of files not yet commited

[supermihi]

First two are fixed in 4165b6f38ecb152859d46eddb4d7ecab3901f7f4. Filesystem browser still needs work:

• allow to delete files
• allow to show stuff in browser