Add a parser factory method, Regex;

Add an Opt parser combinator;

Add an XAtLeastOnce parser combinator.
Add a parser factory method, Regex;

Add an Opt parser combinator;

Add an XAtLeastOnce parser combinator.
Add a Str factory method.
Merge branch 'master' into NewCombinator
Revert the change made to the test project.
Fix the comment bug for Parse.Optional()
Fix the comment bug for Parse.Optional()
Merge branch 'NewCombinator' of git@github.com:winteryoung/Sprache.git into NewCombinator

Conflicts:
	src/Sprache/Parse.cs
Add a parser that can report matched positions.
Merge branch 'master' of git@github.com:sprache/Sprache.git into NewCombinator

Conflicts:
	src/Sprache.Tests/ParseTests.cs
	src/Sprache/Input.cs
	src/Sprache/Parse.cs
	src/Sprache/Sprache.csproj
Merge branch 'master' of git@github.com:sprache/Sprache.git into NewCombinator

Conflicts:
	src/Sprache.Tests/ParseTests.cs
	src/Sprache/Input.cs
	src/Sprache/Parse.cs
	src/Sprache/Sprache.csproj
Merge branch 'NewCombinator' of git@github.com:winteryoung/Sprache.git into NewCombinator

Conflicts:
	src/Sprache/Input.cs
Merge branch 'NewCombinator' of git@github.com:winteryoung/Sprache.git into NewCombinator

Conflicts:
	src/Sprache/Input.cs
Merge branch 'NewCombinator' of git@github.com:winteryoung/Sprache.git into NewCombinator

Conflicts:
	src/Sprache/Input.cs
Merge branch 'NewCombinator' of git@github.com:winteryoung/Sprache.git into NewCombinator

Conflicts:
	src/Sprache/Input.cs
Merge branch 'NewCombinator' of git@github.com:winteryoung/Sprache.git into NewCombinator

Conflicts:
	src/Sprache/Input.cs
Manually fix merge problems.
Manually fix merge problems again.