Pairplots

[Diff since v0.7.0](https://github.com/sefffal/PairPlots.jl/compare/v0.7.0...v0.7.1)

[Diff since v0.6.0](https://github.com/sefffal/PairPlots.jl/compare/v0.6.0...v0.7.0)


**Closed issues:**
- Lens option not working ? (7)
- Labels with spaces (8)
- PairPlots for Makie? (9)

**Merged pull requests:**
- Rewrite for Makie! (12) (sefffal)

[Diff since v0.5.4](https://github.com/sefffal/PairPlots.jl/compare/v0.5.4...v0.6.0)

[Diff since v0.2.0](https://github.com/sefffal/PairPlots.jl/compare/v0.2.0...v0.5.4)


**Closed issues:**
- Remove Plots.jl dependency (1)
- Attempt to save state beyond implementation limit (2)
- Some vectors wont plot? (3)
- [BUG] Incorrect usage of Tables.jl API (4)
- ERROR: Unsatisfiable requirements detected for package PairPlots (5)

* Fix 2D histogram bins being misaligned by 1/2 of a bin
* Layout of plots grid is now much denser using a custom manual layout
* Improved error messages for a few common input issues (e.g. all data in a single bin)
* Relaxed version constraint on StaticArrays
* Plots now pulled in via Requires for some necessary layout functionality (no direct dependency on Revise)
* Added `lens` option to easily show one of the 1D or 2D histograms enlarged in the top right corner
* Improved support for inputting MCMCChains.Chains

Also, added a fun logo to the README:
<img src="images/logo.png" width=50/>