clean unnecessary = on mongodump parameters
Add FILEPREFIX parameter for dump filename
Unify backup file names: first day/week/month and then date, add FILEPREFIX
Not remove latest directory, delete content based on FILEPREFIX
Add support for single database backups
DBNAME parameter
Add support for single collections backups
COLNAME parameter
Update readme with new feature: db-collection backups
added a 7z compression option

Also changed some defaults and updated version history
updated header version
updated script version
Create CHANGELOG.md
Create README.md
Delete README.textile