* Makefile: Added '/r:Microsoft.VisualBasic.dll' to the compile

* Makefile: Added '/r:Microsoft.VisualBasic.dll' to the compile
command line.

* driver.cs (UnixParseOption, CSCParseOption): Added
'/optioncompare:[text|binary]' command line option.

* rootcontext.cs (StringComparisonMode): Added. Keeps track of the
'/optioncompare:' command line option.

* typemanager.cs (InitVisualBasicHelperTypes,
InitVisualBasicCodeHelpers): New routines that preload frequently
used types and helper methods available in
Microsoft.Visualbasic.dll.

(IsFixedNumericType, IsFloatingNumericType,IsNumericType): New
VB.NET specific helper routines. Added in anticipation of a future
use.

* ecore.cs (HelperMethodInvocation): Added. Implements the same
functionality as the earlier vaguely named class
'ImplicitInvocation'. This class uses the 'type cache' of
Microsoft.VisualBasic helper methods now available in the
TypeManager.

* convert.cs (WideningConstantConversions): Reimplemented. The
earlier implementation was completely topsy-turvy.  Propagated the
changes relating to the introduction of 'HelperMethodInvocation'.

* mb-parser.jay: Added rule and action for 'Like' expression.
* mb-tokenizer.cs (keywords): Cleaned up the extra space in the
'let', 'lib' and 'like' entries.

svn path=/trunk/mcs/; revision=42488