Copied all of README.md to installing.md.
Copied all of README.md to installing.md.

GoogleCloudPlatform/gcsfuse,GoogleCloudPlatform/gcsfuse,kahing/gcsfuse,jacobsa/timeutil,GoogleCloudPlatform/gcsfuse,BanzaiMan/gcsfuse,mbrukman/gcsfuse,BanzaiMan/gcsfuse,jacobsa/ratelimit