nimrod dump can now produce a machine readable json report

The data in the report includes necessary information for starting
the compiler service and setting up the project paths in the IDE.

the default verbosity of 1 is now set in the compiler code to fix an
issue with verbosity being temporary set to 1 during config parsing
even when it's explicitly overridden on the command-line.

compiler/lexbase was temporary renamed to nimlexbase as a
work-around for a codegen naming conflict with lib/pure/lexbase
resulting in linking errors (further investigation needed).

compiler/msgs.nim

@@ -83,7 +83,9 @@ type
     errInvalidCommandX, errXOnlyAtModuleScope, 
     errXNeedsParamObjectType,
     errTemplateInstantiationTooNested, errInstantiationFrom, 
-    errInvalidIndexValueForTuple, errCommandExpectsFilename, errXExpected, 
+    errInvalidIndexValueForTuple, errCommandExpectsFilename,
+    errMainModuleMustBeSpecified,
+    errXExpected, 
     errInvalidSectionStart, errGridTableNotImplemented, errGeneralParseError, 
     errNewSectionExpected, errWhitespaceExpected, errXisNoValidIndexFile, 
     errCannotRenderX, errVarVarTypeNotAllowed, errInstantiateXExplicitely,
@@ -301,6 +303,7 @@ const
     errInstantiationFrom: "instantiation from here", 
     errInvalidIndexValueForTuple: "invalid index value for tuple subscript", 
     errCommandExpectsFilename: "command expects a filename argument",
+    errMainModuleMustBeSpecified: "please, specify a main module in the project configuration file",
     errXExpected: "\'$1\' expected", 
     errInvalidSectionStart: "invalid section start",
     errGridTableNotImplemented: "grid table is not implemented",