Remove ability to get column and replace with getting character count from line start

[dsherret]

Silly mistake, but a column should be 1-indexed. For example:

const sourceFile = project.createSourceFile("test.ts", "");
sourceFile.getColumnAtPos(0); // should be 1 and not 0

This applies to getColumnAtPos, getStartColumn and getEndColumn.

[dsherret]

Hmmm... I was looking in visual studio and noticed there's "col" and "ch"... looking it up: https://stackoverflow.com/questions/19226060/what-is-the-col-value-in-visual-studio-text-editor

The difference between column and character positions is evident for characters such as the tab character that can incorporate more than one column

So I have getColumn-like methods implemented completely wrong. I don't think it makes sense to have this function in ts-simple-ast because properly implemented it depends on how the character is displayed (ex. font, character design, tab size).

I'm going to deprecate these methods and replace them with sourceFile.getLengthFromLineStartAtPos(pos); (can't think of a better name atm).