More http sync

- improve docs
- add tests for sync case
- modify http tests so that they now pass
- Still TODO: Update call sites (oauth)
More concise server logging of unexpected errors.

'exception.stack' already contains 'exception.toString()' at the top. The original code printed the exception message twice.
OAuth login services use the new http sync api
Simplify error handling in accounts-facebook
Merge branch 'avital-http' into devel
Update History.md
Simplify server http code by using future.resolver()
Update the readme that gets generated within the .npm folder of packages
Merge pull request #980 from timhaines/npm-readme-update

Update the readme that gets generated within the .npm folder of packages
 Added user agent to account-github's getIdentity() function. This is untested.

See https://github.com/meteor/meteor/issues/981
accounts-github: Generate user agent string from release version
Merge branch 'pr/982' into devel

Conflicts:
	packages/accounts-github/github_server.js
Update History.md
Thank pmark
 Added user agent to account-github's getIdentity() function. This is untested.

See https://github.com/meteor/meteor/issues/981
accounts-github: Generate user agent string from release version
Update History.md

Conflicts:
	History.md
Thank pmark
accounts-github: Also send user agent on oauth login call
0.6.2.1