Resolved#473
I am removing this bit because this advice to not throw on recoverable-from cases like a file failing to open is actually not respected by Nim standard library. `readFile` and `readLines` both throw and exceptions must be used as a method of control flow for the recovery from that. There are alternatives, like opening a file handle instead of using these helpers, but that's less convenient than these helper methods for cases where you really want to just slurp up a file to memory and use a fallback value if it doesn't exist or is for whatever reason not readable.
* Error -> Defect for defects
The distinction between Error and Defect is subjective,
context-dependent and somewhat arbitrary, so when looking at an
exception, it's hard to guess what it is - this happens often when
looking at a `raises` list _without_ opening the corresponding
definition and digging through layers of inheritance.
With the help of a little consistency in naming, it's at least possible
to start disentangling the two error types and the standard lib can set
a good example here.
* tut1: added multiline comments
* tut2: replaced expr/stmt with untyped/typed
* added some more template/macro example
* remove immediate pragma from example
