Labfis

Fixes
- Default rounding using half_down instead of half_up (Issue 10)

Changes
- Labfloat generator using any iterable in argument
- ``labfloat([val1,val2,...],[err1,err2,...])``
- ``labfloat([val1,val2,...],[err1,err2,...],[val1,val2,...],[err1,err2,...],...)``

- Trigonometric methods (can be used using Numpy as function overloaded).
- ``labfloat(pi*3/4,pi/8).sin()``
- ``labfloat(pi*3/4,pi/8).cos()``
- ``labfloat(pi*3/4,pi/8).tan()``

- Square root method (can be used using Numpy as function overloader).
- ``labfloat(241,42).sqrt()``

- Labfloat uses ``__round__`` magic method for uncertainty and mean rouding with python *Decimals* (performance improvement).
- format method replaced with round magic method.

- Improve tests.

Fixes

- Wrong idexing order in mean and uncertainty.
- before: ``labfloat(1,2)[:] == [2,1]``
- now: ``labfloat(1,2)[:] == [1,2]``

- Better Exception messages.

- Bug fixes and other minor changes.

Other Informations
- For more information, a guide will be added later. [WIKI Milestone](https://github.com/phisgroup/labfis.py/milestone/1)

Changes
- Labfloat uncertainty and mean formatter method using python *Decimals* (performance improvement);

- Improve tests precision and logging;

- Bug fixes and other minor changes.

Changes
- Labfloat generator using lists in argument
- labfloat([val1,val2,...],[err1,err2,...])

- Trigonometric functions using Numpy as function overloader.
- sin
- cos
- tan

- Square root function using Numpy as function overloader.

- Numpy soft requirement.

- Bug fixes and other minor changes.

Other Informations
- For more information, a guide will be added later. [WIKI Milestone](https://github.com/phisgroup/labfis.py/milestone/1)

- Fixed missing number cases in 4

- Bug fixes and other minor changes

- Fix wrong number formatting with special cases 4

- Bug fixes and other minor changes