Review: Misc ActiveRecord bug fixes

Thanks to Ray and Joshua for pair debugging this morning!

Module#autoload call should be ignored if the constant is defined.
Without this, a class definition was being lost if autoload was called
after the class definition was executed
(timeObj == “string”) should return nil. It was throwing TypeError
because method overload resolution was finding
System.DateTime.op_Equality. Throwing a TypeError is ok for .NET types
with strongly typed op_Equality, but not for those types that represent
Ruby types.
Fix typo in multi-line regex in YAML engine causing incorrect parsing of
Time yaml strings

Merlin/External.LCA_RESTRICTED/Languages/IronRuby/Yaml/IronRuby.Libraries.Yaml/Engine/BaseConstructor.cshttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-0
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Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/module/autoload_spec.rbhttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-1
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Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/time/eql_spec.rbhttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-2
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Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/time/equal_value_spec.rbhttp://github.com/shri/ironruby/tree/226ceebdd8e64fc86042e626b9de1e96b4226029/Merlin/External.LCA_RESTRICTED/Languages/IronRuby/mspec/rubyspec/core/time/equal_value_spec.rb
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Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Builtins/KernelOps.cshttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-4
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Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Builtins/TimeOps.cshttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-5
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Merlin/Main/Languages/Ruby/Libraries.LCA_RESTRICTED/Initializers.Generated.cshttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-6
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Merlin/Main/Languages/Ruby/Ruby/Builtins/RubyModule.cshttp://github.com/shri/ironruby/commit/226ceebdd8e64fc86042e626b9de1e96b4226029#diff-7
Thanks,
Shri