0.4

• Added new methods: rkv65, rkssp53, rkssp43, rkls54, dverk78, rk5, rkc5, rkl5, rkpp54.
• Added rklib_properties type for storing/retrieving method properties.
• Allocate storage for function evaluations once in the class initialization, rather than every step.
• Eliminated some compiler warnings
• Updates to the unit tests
• Updates to Readme file