Colors.nsh: now more colorful

I took Colors.nsh and added some macros to use with nsis.

• RGB.- Macro to convert red, green and blue integer values to HTML Hex number format.
• Hex.- Macro to convert red, green and blue integer value to Hexadecimal (0xRRGGBB) number format.
• GetRvalue.- Function to get the r value from a RGB number.
• GetGvalue.- Function to get the g value from a RGB number.
• GetBvalue.- Function to get the b value from a RGB number.
• GetRvalueX.- Function to get the r value from a Hex number.
• GetGvalueX.- Function to get the g value from a Hex number.
• GetBvalueX.- Function to get the r value from a HEX number.

Remember: input values are without 0x00 or 0x and #....See example...

Thanks, uploaded.