FIXED visibility of CustomOperator ==================================  - changed Consutrctors from package private to protected (see http://jira.congrace.de/jira/browse/EXP-1)
FIXED visibility of CustomOperator
==================================
 - changed Consutrctors from package private to protected (see http://jira.congrace.de/jira/browse/EXP-1)

Sellegit/exp4j,liangjingyang/exp4j,fasseg/exp4j