Improve translator robustness

[domcharrier]

Current parser is too general and does not take into account that Fortran
statements such as end module mymodule or end do mylabel must be either
terminated with ; or a linebreak.

Examples (wanted behaviour):

Program Hello ! valid

Program Hello; ! valid

Program; Hello ! invalid

Program Hello; Print *, "Hello World" ! valid

Program Hello Print *, "Hello World" ! invalid

Program Hello
   Print *, "Hello World" ! valid