Add tests for FileTypeResolver
Add interface FileTypeResolverInterface
Implement FileTypeResolver
Change haik_files table colmuns.

ext -> original_name
+ note column
Modify Default Database file
Merge pull request #105 from toiee/fix-site-file-table-schema

Fix site file table schema
Add test for calling non-existance plugin
Catch exception on calling non-existance plugin
Merge pull request #106 from toiee/fix-haik-markdown

Fix haik markdown
Rename FileTypeResolver to MimeTypeResolver
Delete FileTypeResolverInterface
Rename test class and unmark incomplete
Modify test for results with mime-type-encoding
Add resolving by extension.

e.g. hoge.jpg => image/jpeg
Merge pull request #107 from toiee/file-type-resolver-interface

File mime-type resolver
Merge branch 'master' into feature-search-plugin