Feature/add docs (#689)

* Add converted docs repo

* Set theme jekyll-theme-minimal

* Removed BC docs, added TOC

* Added TOCs, rewrote most important links in documentation. Linked README to new Github Pages site

* some link fixes

docs/programmers/api-variables/variable-caching.md

@@ -0,0 +1,38 @@
+\$caching {#variable.caching}
+=========
+
+This tells Smarty whether or not to cache the output of the templates to
+the [`$cache_dir`](#variable.cache.dir). By default this is set to the
+constant Smarty::CACHING\_OFF. If your templates consistently generate
+the same content, it is advisable to turn on `$caching`, as this may
+result in significant performance gains.
+
+You can also have [multiple](#caching.multiple.caches) caches for the
+same template.
+
+-   A constant value of Smarty::CACHING\_LIFETIME\_CURRENT or
+    Smarty::CACHING\_LIFETIME\_SAVED enables caching.
+
+-   A value of Smarty::CACHING\_LIFETIME\_CURRENT tells Smarty to use
+    the current [`$cache_lifetime`](#variable.cache.lifetime) variable
+    to determine if the cache has expired.
+
+-   A value of Smarty::CACHING\_LIFETIME\_SAVED tells Smarty to use the
+    [`$cache_lifetime`](#variable.cache.lifetime) value at the time the
+    cache was generated. This way you can set the
+    [`$cache_lifetime`](#variable.cache.lifetime) just before
+    [fetching](#api.fetch) the template to have granular control over
+    when that particular cache expires. See also
+    [`isCached()`](#api.is.cached).
+
+-   If [`$compile_check`](#variable.compile.check) is enabled, the
+    cached content will be regenerated if any of the templates or config
+    files that are part of this cache are changed.
+
+-   If [`$force_compile`](#variable.force.compile) is enabled, the
+    cached content will always be regenerated.
+
+See also [`$cache_dir`](#variable.cache.dir),
+[`$cache_lifetime`](#variable.cache.lifetime),
+[`$cache_modified_check`](#variable.cache.modified.check),
+[`is_cached()`](#api.is.cached) and the [caching section](#caching).