v0.4.2

Quiqbox v0.4.2

Diff since v0.4.1

Merged pull requests:

• 0.4 Optimzation Dev (#70) (@frankwswang)
• 0.4-Performance Dev (#71) (@frankwswang)
• 0.4-Optimization Dev (#72) (@frankwswang)
• 0.4.2-Performance Dev (#73) (@frankwswang)
• Improved the pfrm and stability of m-threading. (#74) (@frankwswang)
• Updated the package version number. (#75) (@frankwswang)