Start rule set implementation
- Add rule() function
- Generate empty rule files for Visual Studio 201x

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Clean up namespace usage in action.lua

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Rename project.getfilename() to premake.filename(); now used by rules too

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Add opening XML and project elements to rule files; consolidate common code

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Fill in generated skeleton of Visual Studio VS 201x rule files

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Split rule file generation into namespaces to prevent function name overlaps

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Add location() and filename() support for generated rule sets
- Enable new top-level field scope "rule"

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Introduce configuration container API; reimplement rules as a container class

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Begin implementation of property definitions for generated rules
- add new API propertyDefinition() with name, kind, and default value keys
- write default values to Visual Studio .props files

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Rework filter() and configuration() to support new container hierarchies; can now use on rules

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Add rule .props file support for buildCommands, buildOutputs, buildMessage, buildDependencies

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Fill in more easy bits in generated rule .targets

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Complete generation of simple .targets files

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Added basic support for enum and list rule properties

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Merge with development branch

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Basic support for boolean properties, some fixes

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Restore XML declaration extension point for VC 201x projects

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extra : amend_source : e99c4243a4431383ebc71231a8713004059475ec
Merge latest development branch

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branch : feature/rules
Merge Visual Studio indentation fixes

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Fill in more command line properties; add file extension

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branch : feature/rules