Updates for preparing release v1.0.0

[tridelat]

In this PR, a few overdue fixes:

• Tests more thorough by comparing full .csv results for tension components
• Added more tests:
  • Multisegmented rigid and elastic cases
  • Rigid cable with no floor (single segment and multisegmented)
  • Anchor above fairlead (rigid cable with no floor)
• Use new sign convention for tension (horizontal tension pointing towards trough of catenary, vertical pointing downwards)
• Integrate tension more accurately for calculating elongation
• Fix fully rigid catenary lines by passing EA=None (also works for multisegmented lines)
• More accurate coordinates retrieval for elongated lines
• Convenience functions for tension at fairlead/anchor
• Handles cases where anchor is above fairlead

[tridelat]

Bumping this to preparation of v1.0.0 since most intended features and tests are introduced