Add FixedWidthTwoLine Reader to guess list

As discussed in #3025 and #3099, it would be useful if tables that are copied
from the screen (where the defaul print format is something like)
```
col1 col2
---- ----
1.0  2.0
3.0  44.0
```
into a file could be read automatically with the guessing process.

closes #3099
closes #3025
Allow extra spaces in the fixed width marker line
Add test to allow only certain chars in postion line.
allow extra white spaces in position line
Merge pull request #3109 from hamogu/no_YAR

Add FixedWidthTwoLine Reader to guess list