Fortran-language-server

Fixes
* Fix case preservation in hover requests, fixes [102](https://github.com/hansec/fortran-language-server/issues/102)
* Fix rename requests for type-bound procedures without an explicit link statement (ie. "=>"), fixes [104](https://github.com/hansec/fortran-language-server/issues/104)
* Fix incorrect "CONTAINS" diagnostic errors with procedure pointers and external interfaces
* Fix bug in diagnostic construction/reporting (introduced in v1.7)
* Fix bugs caused by accidental modification of child object lists

Fixes
* Fix bug with definition/hover requests involving intrinsic functions/modules/variables (introduced in v1.7)

Fixes
* Fix bug with completion and signatureHelp requests on continuation lines (introduced in v1.7)
* Fix out-of-range error with various requests on zero-length lines (introduced in v1.7)

Improvements
* Add initial support for "textDocument/codeAction" requests, generate unimplemented deferred procedures
* Show subroutine/function keywords ("PURE", "ELEMENTAL", etc.)
* Add position of object in line to "textDocument/definition" and "textDocument/implementation" results
* Diagnostics: CONTAINS statement placement errors
* Diagnostics: Visibility statement placement errors
* Command line options: Notify when workspace initialization is complete
* Command line options: Set number of threads used during initialization
* Significant refactoring of core code

Fixes
* Fix "RecursionError" exception with circular user-defined type references, fixes [100](https://github.com/hansec/fortran-language-server/issues/100)
* Fix bug detecting TYPE definitions with an immediately following colon, ref [100](https://github.com/hansec/fortran-language-server/issues/100)
* Fix incorrect diagnostics for interface statements with USE instead of IMPORT statements

Improvements
* Add support for EXTERNAL subroutines
* Diagnostics: Missing subroutine/function arguments and argument declarations
* Diagnostics: Unimplemented deferred type-bound procedures
* Diagnostics: Unknown TYPE/KIND objects (only if candidate is visible in workspace)
* Diagnostics: IMPORT statements (missing objects and placement)
* Diagnostics: Basic handling for IMPLICIT statements

Improvements
* Add support for semicolon separators and multiline preprocessor macros, fixes [98](https://github.com/hansec/fortran-language-server/issues/98)
* Add various "parsing errors" to debug_parser output

Fixes
* Use consistent file access method across debug_parser run and language server requests