Clean and bug fix

Revert "Swift Bool"

This reverts commit 0ffb910fcefd21203f248e06509a2374c1369571.

Bug fix and improvement

1. fix and improved rendering intent
2. FileBuffer
3. atomic bug fix

Improved API

Improved API

Improvement

• New MappedBuffer type for handling large buffers.
• Protocol-oriented graphic types

Swift 4

Swift 4 is coming!