Npp mime tools v2.6 release

1. Add arm64 support.
2. Fix an eventual crash for SAML Decoding.
3. Update GPL from v2 to v3.
4. Update header files.

be0d8b71c454b09d6d384e0bba87d25932c1563a2eb4871b070617fbca8ecaa6  mimetools.v2.6.arm64.zip
4135ea174f741f053f759b194dc8e506fd96c2ef3d1d7a43971446fe53223897  mimetools.v2.6.x64.zip
6ad8d200b3f03a4b27df8a7e34c023b89a01ade971945b17ae4b61cdbc3d2abf  mimetools.v2.6.zip