Fix to seurat subset issue and updated screenshots

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (0cdc45b) 52.76% compared to head (d70123a) 52.77%.

:exclamation: Current head d70123a differs from pull request most recent head f9baea3. Consider uploading reports for the commit f9baea3 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## devel #718 +/- ## ======================================= Coverage 52.76% 52.77% ======================================= Files 79 79 Lines 12695 12696 +1 ======================================= + Hits 6699 6700 +1 Misses 5996 5996 ``` | [Files Changed](https://app.codecov.io/gh/compbiomed/singleCellTK/pull/718?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=compbiomed) | Coverage Δ | | |---|---|---| | [R/seuratFunctions.R](https://app.codecov.io/gh/compbiomed/singleCellTK/pull/718?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=compbiomed#diff-Ui9zZXVyYXRGdW5jdGlvbnMuUg==) | `73.24% <100.00%> (+0.03%)` | :arrow_up: |

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