add CsarRepository wip #17

move sessionGeneration in helper-Class
Merge pull request #37 from eiselems/17

add CsarRepository class refs #17
implemented repository for csarfile, fixes #18
propagate exception, review #18
refactor FileSystem

-use UUID to generate filenames
-retrieval/deletion by absolute paths

add new method to save temp file

remove id from method header
Merge pull request #38 from przytads/18

implemented repository for csarfile, fixes #18
Merge pull request #40 from eiselems/fileSystem_refactoring

refactor FileSystem
add UploadCsarService refs #19
Merge pull request #41 from eiselems/19

first implementation of UploadCsarService, needs to be extended, refs #19
implemented list csar service, fixes #22
add CsarFile to hibernate.cfg.xml
fix FileSystem refs #44
Merge pull request #46 from eiselems/45

add CsarFile to hibernate.cfg.xml, fixes #45
Merge pull request #43 from przytads/22

implemented list csar service, fixes #22
Merge pull request #47 from eiselems/44

fix FileSystem refs #44
Reimplemented DownloadService, refs #20
Merge pull request #48 from TKosch/20

Reimplemented DownloadService, fixes #20
Refactored hibernate model and extended with annotations. Used UTC in
hibernate cfg as standard timezone, refs #49
Removed unused methods and made field names consistent
Merge pull request #50 from TKosch/49

Annotated hibernate model and refactored it, fixes #49