KFileMetaDataProvider: Don't crash if a Strigi analyzer crashes

Some Strigi analyzers are still unstable and crash under certain circumstances. This patch moves the reading of the meta-data into a custom process instead of doing it in a thread, which assures that a crashing Strigi analyzer does not result in crashing Dolphin or Konqueror when hovering some items.

FIXED-IN: 4.7.0
BUG: 257964
BUG: 258715
BUG: 262299
BUG: 263468
BUG: 263502
BUG: 264254
BUG: 234799
BUG: 251462
BUG: 251701
BUG: 258918
BUG: 192377
BUG: 195564
BUG: 199368
BUG: 210841
BUG: 245376
BUG: 246461
BUG: 246901
BUG: 249150
BUG: 261952
BUG: 249876
BUG: 179376
BUG: 179417
BUG: 179420
BUG: 181591
BUG: 183269
BUG: 183722
BUG: 185667
BUG: 188596
BUG: 191864
BUG: 193112
BUG: 205813
BUG: 244621
BUG: 245451
BUG: 248214
BUG: 249655
BUG: 249876
BUG: 265549
BUG: 267079