Changes from version 1.2.1 to 1.2.2
 * Added package vignette. Updated the simplification procedure to handle more situations.

Changes from version 1.2.0 to 1.2.1
 * Revised the simplification algorithm. The structure of the graph is now utilized.

Changes from version 1.1.3 to 1.2.0
 * Major revision which adds more algorithms for causal inference.

Changes from version 1.1.1 to 1.1.3
 * Fixed an error related to function definitions.
 * Fixed compatibility with igraph package version 1.0.1.

Changes from version 1.1.0 to 1.1.1
 * Fixed an issue that caused the results of some conditional causal effects to be erroneous.

Changes from version 1.0.0 to 1.1.0
 * Added functionality to identify conditional causal effects.