The original intent of #12056 was to improve parsing recovery in the
cast of a leading accessibility modifier on a local function. However, I
mistakenly allowed for recovery for an accessibility modifier *anywhere*
in the modifier list of the local function.

This is a mistake because it significantly complicates parsing back-out.
While it's easy to recognize that the local function parsing failed and
skip any leading accessibility modifiers, it's significantly more
complicated to find and skip all accessibility modifiers anywhere in a
sequence of modifiers.

This PR changes the parsing backout to only consider accessibility
modifiers at the start of statements. Any other case will be treated
like other bad modifiers in local functions -- they will be marked as
errors in the declaration list. Fixes #12947.

Make the binder resilient to ref type and ref expression nodes.

Misc. changes for Task-like type support

add vs project guid in compilation input telemetry

Adjust scope of locals declared within Expression Statements according to the latest design.

Add Codelens service for VS

Split syntax generation into three files

reduce creating default Task.FromResult tasks.

Merge VB tuples from a feature branch into Master

Instrumenting field initializers and implicit constructors for dynamic analysis

Entered tracking bugs instead as customary when merging into Master branch.

Support calls to ByRef return methods in VB

Add DebuggerDisplay attributes.

Walk converted tuples in flow analysis

Fix completion API based on API review.

Fixes #12746

Related to #12597.

Don't offer to add a using for the namespace that the code is already contained within

Fixes #11608
Fixes #9597

Merge dev15-preview-4-df into master-20160809-150104

Fix bad casing for argument parsing in RepoUtil.

Merge remote-tracking branch 'upstream/dev15-preview4-df' into merge-dev15-preview-4-df-into-master20160809-150104

Merge from recent master into vbTuples