Improve compiler error reporting

[lock9]

Problem

The compiler may fail without informing where the error is coming from. I found at least two places that can be fixed.

Solution

Include the file line and position of the error message

Output example:

error while trying to compile smart contract file: .../abstract.go:101:9: '&' can be used only with struct literals

Note: I didn't find test cases covering this error so I didn't add any new test.