Merge pull request #87 from guidow/tag_api

Don't need to manually delete relations on a tag
Merge pull request #88 from guidow/typo_corrections

Minor typo corrections in some docstrings
Merge pull request #89 from guidow/refactor_requirements

Refactor Software, separate tables for versions, SoftwareRequirements
pip switched on exclusion of external packages, add an exclusion for mysql-connector-python
wrong place for --allow-external, updating general configuration
doctring updates
doctring updates and minor usage fixes
fixes to tests
typo fix
#93 only needs a single html template now
create templatable error_handler for #93
updating entrypoints with new implementation for error handling in #93
should be checking to make sure the http code is valid, #93
adding tests for #93
updated to new decorator and g.json for #52, also optimized lookups
adding the ability to ignore specific fields (useful for PUT) for #52
readding handling for int based PUTs for #52
imporved error messages for #52
adding autoincrementing attr
adding disallow column to validate_with_model for #52