fixed broken url in instrucctions

The current domain to access raw files is
https://raw.githubusercontent.com
Merge pull request #9 from neosergio/master

fixed broken url in instrucctions
Make ssh-copy-id.sh executable
Make install.sh executable
Improved install.sh.

Allows the install script to be curled directly from GitHub for easy install:

	curl http://URL/TO/install.sh | sh
Update README.txt to show easy installation method