FIXED: use decryptLegacy() for old logindata

 * Use old decrypt method when decrypting oldest logindata format
FIXED: check natives when force updating
FIXED: gatherAssets() and setupNewStyle()

 * gatherAssets():
   handle exceptions from download()
   try downloading multiple times
 * setupNewStyle:
   fixed NPE
FIXED: UserManager: null bytes in logindata

 * Try to if logindata is malformed
 * Still WIP. Should it first bytes from login data and then delete file
   if broken?
Refactoring

 * Moved GUI code from swingworker to worker creator code
Merge pull request #730 from jikuja/fixes_for_1.3.10_v3

Fixes for 1.3.10 v3