Updated the mail parser to handle plaintext
Updated the mail parser to handle plaintext

This change allows us to detect the header type of inbound emails and
prevents html being cleaned when the type is "text/plain".

JanSiero/SuiteCRM,gody01/SuiteCRM,samus-aran/SuiteCRM,JimMackin/SuiteCRM,horus68/SuiteCRM-Horus68,Dillon-Brown/SuiteCRM,ChangezKhan/SuiteCRM,ChangezKhan/SuiteCRM,Dillon-Brown/SuiteCRM,MikeyJC/SuiteCRM,horus68/SuiteCRM-Horus68,gody01/SuiteCRM,gody01/SuiteCRM,MikeyJC/SuiteCRM,JanSiero/SuiteCRM,lionixevolve/SuiteCRM,MikeyJC/SuiteCRM,lionixevolve/SuiteCRM,pribeiro42/SuiteCRM,horus68/SuiteCRM-Horus68,MikeyJC/SuiteCRM,lionixevolve/LionixCRM,ChangezKhan/SuiteCRM,gody01/SuiteCRM,ChangezKhan/SuiteCRM,JimMackin/SuiteCRM,Dillon-Brown/SuiteCRM,lionixevolve/LionixCRM,JimMackin/SuiteCRM,horus68/SuiteCRM-Horus68,pribeiro42/SuiteCRM,JanSiero/SuiteCRM,salesagility/SuiteCRM,lionixevolve/LionixCRM,lionixevolve/LionixCRM,lionixevolve/LionixCRM,lionixevolve/LionixCRM,lionixevolve/SuiteCRM,lionixevolve/SuiteCRM,salesagility/SuiteCRM,JimMackin/SuiteCRM,Dillon-Brown/SuiteCRM,pribeiro42/SuiteCRM,salesagility/SuiteCRM,JanSiero/SuiteCRM,samus-aran/SuiteCRM,samus-aran/SuiteCRM,salesagility/SuiteCRM,pribeiro42/SuiteCRM,samus-aran/SuiteCRM