Don't smart-allocate anything when creating the execution context

Summary: We (re-)create the execution context at the end of every
request. If it smart allocates anything, we will end up allocating
a 2Mb slab which won't be freed (or used) until the next time
the thread executes a request. Since we typically have a lot of
idle requests, this could be a significant chunk of memory.

Reviewed By: @bertmaher

Differential Revision: D1465987
Make ProfilerLevel into enum class; give it a better name

Summary: It may have been intended as a profiling "level" originally, but it's
not that anymore. Rename, make enum class. This makes it easier to grep
for where these things are being used.

Reviewed By: @ptarjan

Differential Revision: D1478966
Add better error reporting if framework runner ran without an HHVM build

Summary: See confusion on facebook/hhvm#3320

cc GrahamCampbell

Reviewed By: @JoelMarcey

Differential Revision: D1478146
Delete SimpleProfiler

Summary: ProfilerKind::Simple was unused except for that case label, and there
was no other way to instantiate a SimpleProfiler. SimpleProfiler also
returned its results by directly writing some nasty HTML (referencing
nonexistent css and js files) to output. Everything else in this file is
more than enough to cover this functionality; let's kill it.

Reviewed By: @ptarjan

Differential Revision: D1480436
Make whitespace in reflectionparameter match php5

Summary: refs facebook/hhvm#3320

Reviewed By: @JoelMarcey

Differential Revision: D1475355
Compatibility fill ins

Summary: backtrace, min/max macros, and some other compatibility fixes for cygwin

Reviewed By: @sgolemon

Differential Revision: D1480306
typechecker: enforce default constructor consistency

Summary: A class with no defined constructor may still want to use
 `<<ConsistentConstruct>>` when it contains a `new static()`; allowing
 child classes to define a constructor with mandatory args would not
 be acceptable.

Reviewed By: @jwatzman

Differential Revision: D1477764
Update laravel to v4.2.8

Summary: 100% :) fixes facebook/hhvm#3320

Reviewed By: @JoelMarcey

Differential Revision: D1475474
Upgraded guzzle4 to 4.1.6 in the framework tests

Summary: The passed tests changes from `93.01%` to `92.54%`.

Old stats:

    Tests: 660, Assertions: 1575, Failures: 3, Errors: 43, Skipped: 2.

New stats:

    Tests: 686, Assertions: 1628, Failures: 3, Errors: 48, Skipped: 2.

You can see the old and new error logs here: https://gist.github.com/GrahamCampbell/826d87c35e3049f683dc.
Closes https://github.com/facebook/hhvm/pull/3368

Reviewed By: @fredemmott

Differential Revision: D1479961

Pulled By: svcscm