App doesn't validate folders names correctly

[gguillotte]

Steps to reproduce:

• In Syncthing Android client, tap Add Folder
• Tap Folder ID
• Give the folder a name that includes spaces
• Select a directory
• Tap create

Expected behavior:

• Client refuses to create a folder with spaces in the folder name

Observed behavior:

• Prompts for restart
• Folder is added with spaces in the name
  2014-10-13 22 25 44
• Folder name is not visible on the android web client
  2014-10-13 22 26 25
• Can't add the folder from another device's web client:
  spaces

syncthing-android version: 0.5.2 (F-Droid latest)

Device name and Android version: Nexus 4 Cyanogenmod 11 2014-09-16 M10/Android 4.4.4

versions of involved syncthing nodes: 0.10.1 desktop Windows

config.xml: here