Refactor the code to make it easy for testing

[Habush]

This PR moves out the fiber channels argument from the pattern matcher search functions to the outer annotation functions to make easy to test those functions. Also makes the parser testable and fixes the parser tests

[tanksha]

Where could this module be located?

https://github.com/Habush/annotation-scheme/blob/master/annotation/util.scm#L28

[tanksha]

@Habush please fix the following

• There is an error which hangs the execution of main-tests, it is related to the parse-request function. The function accepts only one argument, two were given here https://github.com/Habush/annotation-scheme/blob/master/tests/main-tests.scm

I fixed that, but got another error

ERROR: In procedure string->symbol:
In procedure string->symbol: Wrong type argument in position 1 (expecting string): #f

Please try to run it first

• One test failed from go-tests, here is the log

  
  test-name: go-regulates
  location: tests/go-tests.scm:16
  source:

• (test-equal
• "go-regulates"
• 3
• (length
• (find-go-plus (ConceptNode "GO:1903896")))) expected-value: 3 actual-value: 0 result: FAIL

• The whole tests from string-test.scm failed with unbound-variable error please check them

[Habush]

@tanksha Fixed the test issues. Please check