Implement readRequiredOption. Fixes #442.

Also renamed getOption to readOption to better highlight that the function may only be called once to read a certain option.

The dissonance in "required option" is a bit unfortunate, but I didn't find a better name overall that is still consistent with the non-required (erm.. optional) version. Also, adding an additional parameter to getOption/readOption would have been not very beautiful either, because then the boolean return value would be partially redundant.
Fix handling of yielded tasks so that events are still processed, when a task continuously calls `yield()`
Updating Homebrew information

brew installation command and installation link
Merge pull request #459 from bearcherian/patch-1

Updating Homebrew information
Use getaddrinfo and parse /etc/hosts on linux - fixes #289.

TODO: for windows, look at \WINDOWS\system32\drivers\etc\hosts

See also #460.
Make NetworkAddress fully pure nothrow.
Fix DNS queries from inside tasks, add hosts file support for non-Linux systems and adjust code style. See #460, #289.
Fix compilation on DMD 2.063.2.
Fix invalid assertion for IPv6 handling.
Add some trace logging for the libevent timer code to better debug #458.
Update web.d
Merge pull request #463 from UplinkCoder/patch-1

change "wen" to "web"
Update rest.d
Merge pull request #464 from UplinkCoder/patch-2

Fixed small typo
Update common.d
Merge pull request #465 from UplinkCoder/patch-3

fix grammer in ddoc