Issue #2499823 by dylanf, ryanissamson, snehi, visabhishek, cilefen, David_Rothstein, DamienMcKenna: Minor CHANGELOG.txt formatting

6.37 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

6.36 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

6.35 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

Issue #2387745 by zealfire, joachim: docs for watchdog() should state character limits, and give error levels

6.34 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

6.33 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

6.32 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

6.31 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

6.29 release

Conflicts:
	CHANGELOG.txt
	modules/system/system.module

Issue @2062127 by rhm50, jlindsey15, joachim: Fix documentation of system_requirements() to say it is a hook implementation

Issue #1629994 by oadaeh, Aron Novak, yurtboy: Reference correct RFC in mail functions documentation

Issue #699604 by cam8001, Albert Volkman: Change links to form API reference to just use the file name