Added Categories Support for Posts

[manikmagar]

Implemented Categories Support for Posts.

Categories configuration controls -

• template.category.file=category.ftl (This is for rendering individual category page)
• template.categories.file=categories.ftl (This is for rendering all categories list page to prevent directory listing on {site.host}/categories/ url.
• categories.enable=true
• render.categories=true
• category.default=Uncategorized
• categories.path=categories
• categories.sanitize=false

Adding categories in content

Add an attribute categories=Category1, Category2

• If categories.enable is not false and no categories are provided for post then category.default is applied to post.
• First category is also available with primary_category key in model.
• If categories.enable is false and categories are still provided in content, then those are ignored with a warning in log.

Accessing categories in templates

• all_categories - All categories from all published content. This variable is available on templates.
• category_posts - On a single category page template.category.file, this variable is available and provides access to posts marked with category being displayed on page.

Test cases

Appropriate test cases have been added under src/test/java with its resources under src/test/resources.

[manikmagar]

This should close Categories part from #284.

[coveralls]

Coverage increased (+0.9%) to 66.071% when pulling 1d78951 on manikmagar:master into 90b8375 on jbake-org:master.

[manikmagar]

@jonbullock please check this.

[coveralls]

Coverage increased (+1.1%) to 66.112% when pulling a41569c on manikmagar:master into 07dd157 on jbake-org:master.

[coveralls]

Coverage increased (+1.1%) to 66.112% when pulling a41569c on manikmagar:master into 07dd157 on jbake-org:master.

[coveralls]

Coverage increased (+1.1%) to 66.112% when pulling a41569c on manikmagar:master into 07dd157 on jbake-org:master.

[manikmagar]

Something went wrong with my forked repo. I will submit a fresh pull request. DO NOT merge this one.