Fixed Tls initialization problem

Visual Studio optimization removes GetTlsIndex class constructor execution in release builds, due to it's not used anywhere. So the previous code has never initialized tlsIndex variable with anything. Such behavior sometime caused the crashes due to error code was not saved into unallocated TLS. 
I've made the explicit calls of GetTlsIndex methods to force class instance creation.
p.s. You may see it yourself how TlsGetValue() fails each time by running the release build under MS Application verifier.
TSK_FS_INFO must be deallocated via tsk_fs_free

Otherwise the critical section in TSK_FS_INFO is not freed
Fixed critical section leak in TSK_FS_INFO
Fixed critical section leak in TSK_FS_INFO
Fixed critical section leak in TSK_FS_INFO
Fixed critical section leak in TSK_FS_INFO
Merge pull request #286 from antonkukoba/patch-4

TSK_FS_INFO must be deallocated via tsk_fs_free
Merge pull request #285 from antonkukoba/patch-3

Fixed Tls initialization problem
Fixed off by 1 error in new ISO sanity check code
Merge branch 'master' of github.com:sleuthkit/sleuthkit