added most equations in planet and star classes, the rest rely on assumptions which need to be implemented.
added the assumptions module for very basic type checking
added mass and temp type checking to planet class (from assumptions)
added mu and albedo assumptions
mu and albedo implemented into planet class
First implementation of a database class. Added search planet feature by using db.searchPlanet()

Thanks to marc-antoine <ma.martinod@free.fr> for some of the search code
Added Repr Methods (may now replace search dict output with list)
add transiting planet list to database
removed dictionaries as the __repr__ methods render them pointless
Merge branch 'feature/equations' into develop
changed package to use default quantities module and it adds units from astroquantities
changed search to only return object not dicts
first step to create a stand alone module
Modularised the package. It is now imported and initialised by the user specifying a database location. All loading code move into database class.
Merge branch 'feature/finishingTouches' into develop
Final changes for first release. Readme, some bug fixes, typo corrections and missing methods