Travis-CI script update

Switched over to Miniconda for compatibility
REF: Moved load_file from Data class to separate method

load method now creates a data class and supports 'auto' detection of filetype.

Also some basic refactoring to reduce line lengths.

Tests and docs updated to reflect changes.
ADD: Load and save methods

Added load and save methods to create Data object from file or list of files.

Includes auto-detect data type.
Fixed docstrings.
Removed load_file from Data class definition.