made basic ScriptExecution acceptance tests run under both debug and non-debug
Add support for global opts file - fixes #768

FileSystem.GlobalOptsFile will return the path for a scriptcs.opts file
in the ModulesFolder

ArgumentHandler looks for non-default option values first from the
command line, then from a local opts file if it exists, and finally from
a global opts file if it exists.

Rename ModulesFolder to GlobalFolder per discussion on #768

Update ShouldUseScriptOptsIfParsingFailed: parser mock will create a
ScriptCsArgs instead of returning null to avoid null reference exception
force the use of trace in Mono engine and in Roslyn engine - on first execution only
separated StringExtensions into its own file
undefine should be #undef
Merge pull request #825 from filipw/feature/trace

defined TRACE
updated to Mono.Csharp 3.6.1
removed InteractiveBase from MonoHost
Merge pull request #828 from filipw/feature/interactivebase

removed InteractiveBase from MonoHost
Merge pull request #827 from filipw/feature/mono361

updated to Mono.CSharp 3.6.1
added System.Net.Http to defaults
adjusted tests
Merge pull request #829 from filipw/feature/System.Net.Http

Added System.Net.Http to defaults
Added constant for config filename
Add fix to pull out the inner exception when an AggregateException is returned from Roslny
Merge pull request #773 from ryanrousseau/opts2

#768 Add support for global scriptcs.opts file
Adding same fix for mono
Merge pull request #834 from glennblock/dev

Add fix to pull out the inner exception when an AggregateException is returned from Roslyn
Merge pull request #807 from adamralph/nondebug-acceptance-test

made basic ScriptExecution acceptance tests run under both debug and non-debug
README.md directions when Chocolatey install fails with 407

Chocolatey installation can fail behind a proxy requiring authentication due to [HTTP 407](http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.8). This change provides an additional command line invocation for those cases that uses the default credentials for proxy authentication prior to downloading.