Accept a default value for read-flycheck-checker
Use last used checker as default when selecting
[Fix #428] Prompt for a checker in flycheck-compile
Reorder definitions to fix free variable warning

Need to move the function definitions after the definition of
flycheck-last-checker which is used in an interactive form
Merge branch 'make-flycheck-compile-prompt'

* make-flycheck-compile-prompt:
  Reorder definitions to fix free variable warning
  [Fix #428] Prompt for a checker in flycheck-compile
  Use last used checker as default when selecting
  Accept a default value for read-flycheck-checker
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