0.1.9 Release

Description

• Bugfix #7 - ([BUG] - TypeError raised on technique.tools)
• Bugfix #2 - ([BUG]: The documentation refers to a wrong file name)
• Edited README.md:
  • Fixed registered references for MITRE
  • Added alternate installation instructions
  • Added Contributing mention
• Added CONTRIBUTING.md
• Edited .gitignore:
  • Excluded enterpriseattack/enterprise-attack.json (test data)
• Added tests/technique_test.py