Merge pull request #7 from apngasm/refactor

Refactor
Update README.md
Update README.md
Update README.md
added missing includes needed on OSX
disasm fix
Implements XmlSpecReader.
Add error check.
Use default delay if argument is illegal.
Move implement of method to cpp.
Merge remote-tracking branch 'origin/maxstepin-fixed-disasm' into xml

Conflicts:
	src/apngasm.cpp
Optimize include header.