### pdbreescape - regexp escape strings from a column

`pdbreescape` passes the requested columns (-k) through python's
regex escaping function.

**Note: because -k can take multiple columns, input files likely need
to appear after the "--" argument-stop-parsing string.*

#### Example input (*myfile.fsdb*):

```
#fsdb -F s col1:l two:a andthree:d
1	key1	42.0
2	key2	123.0
3	key1    90.2
```

#### Example command usage

Using our standard input file for this documentation set, we first
pass the file through `pdbaddtypes` to change the type from a float
to a string, and then escape the period in the (now string) floating
point number:

```
$ pdbaddtypes -t andthree=a -- myfile.fsdb |
  pdbreescape -k andthree
```

#### Example output

```
#fsdb -F t col1:l two andthree
1	key1	42\.0
2	key2	123\.0
3	key1	90\.2
#   | /home/hardaker/.local/bin/pdbreescape -k andthree
```

#### A more complex file (*mystrings.fsdb*)

This shows a greater number of regex escaping types.  Note that the
spaces are also escaped.

```
#fsdb -F t type value
wild-cards	* and . and + and ?
parens	() and []
slashes	/ and \
```


#### Example command usage

```
$ pdbreescape -k value -- mystrings.fsdb
```

#### Example output

```
#fsdb -F t type value
wild-cards	\*\ and\ \.\ and\ \+\ and\ \?
parens	\(\)\ and\ \[\]
slashes	/\ and\ \\

```