(minor) documentation fixes

[sboosali]

some suggestions:

• link to the examples under app (and imo, rename the directory to examples).
• inline some examples (or sections thereof) into the README. for example, mention which lines are internal to the project, and which are external (in particular, prettyprinter functions).
• add PackageImports to example files, for clarity.
• add qualified imports to example files, for clarity (in particular, PP or something for prettyprinter)
• show escaping behavior in an example (unless I'm misunderstanding one of the comments I read, only escape sequences for newlines and tabs are preserved; the rest, like the escape character \ESC, must be done in other ways, like with annotate).

i can do these (or whichever subset you want), if you're interested.

[lpeterse]

Feel free to add PRs. I broke most examples in master right now. Might be a bit too early for fine-tuning right now, though.

[sboosali]

will do (and thanks for the prompt replies!)