Introduce a get_dictionary_property function to reduce duplicated code in the dictionary conversion codegen.

This also explicitly disallows dictionary members without a default value, as
the code for those doesn't currently compile.

This is the second step of my planned rewrite of the dictionary initialization
that will remove the default values we currently use to initialize the
dictionary struct in the 'new' function.
Don't panic on https #2104
auto merge of #2167 : Ms2ger/servo/get_dictionary_property, r=jdm

...the dictionary conversion codegen.

This also explicitly disallows dictionary members without a default value, as
the code for those doesn't currently compile.

This is the second step of my planned rewrite of the dictionary initialization
that will remove the default values we currently use to initialize the
dictionary struct in the 'new' function.
Add expected failures.
auto merge of #2169 : Ms2ger/servo/wpt-expected, r=jgraham
Mention automake and cmake

Fixes #2168
auto merge of #2171 : evilpie/servo/patch-1, r=pcwalton

Fixes #2168
auto merge of #2166 : campadrenalin/servo/https-dont-panic, r=jdm

This is a stab at #2401 - I think this was what @jdm had in mind for a fix.

I've also included a test. There's no "i tried" star, I'm too much of a newb for that, but hopefully the test at least confirms that servo doesn't crash on HTTPS requests.