Add VariableProperty API.

Allows accessing properties of Context Variables and Values.

Fixes #8
Clean up README a bit.
Clarify RuleBuilder operator documentation.

Add additional parameters to method signature and documentation, indicate that they’re unlimited and optional.

See #10
Unset should work even if the property isn’t set.

See #8
markdown -> md
Add PHPUnit dev dependency.
Adding test namespace

I'd like to be able to use the fixtures in your unit tests for the ZFRuler module I'm building.
Add PHP 5.5, new composer call to Travis config.
tests, not test
Rearranging namespace loading for tests
pointing bootstrap at composer autoload.php
Altering vendor path so travis will pass.
Merge pull request #13 from zburnham/add_composer_namespace

Adding test namespace
Adding SameAs and NotSameAs operators

Signed-off-by: Christophe Sicard <sicard.christophe@gmail.com>
Adding tests and docs to SameAs and NotSameAs operators
Merge pull request #14 from tophsic/sameasnotsameas

Adding SameAs and NotSameAs operators
Refactor RuleBuilder variable, property classes.

Separate the RuleBuilder fluent DSL concerns from the base Variable and VariableProperty classes.

The RuleBuilder VariableProperty would have been better implemented as a trait, but PHP 5.3, eh?
Add a VariableProperty trait.

Use this when creating extended RuleBuilder DSLs with custom operators and magick like that.

It doesn't do *us* any good, since we're targeting PHP 5.3 with this library, but it does help on the extensibility front.
Merge pull request #17 from bobthecow/feature/builder-concerns

Extract the RuleBuilder DSL from the base Variable and VariableProperty classes.
Add Arithemtic Ops and refactor Base Ops

Add these operators:
Addition
Ceil
Division
Exponentiate
Floor
Max
Min
Modulo
Negation
Subtraction

Add these Operator Classes:
UnaryOperator
BinaryOperator
MultipleOperator

Refactor All existing Operators to extend from one of those bases.