Gov. Charlie Baker on Wednesday is filing a $40.5 billion budget for fiscal year 2018, boosting state spending by around $1.655 billion while also calling for reforms to the health insurance market and tax policy changes aimed at responding to modern commerce.  Baker’s third annual budget represents 4.3 percent gross spending growth over projected spending for the current fiscal year, including a $997 million increase for MassHealth, a $117 million increase in education spending, a $29 million increase in debt service and a $40 million increase in unrestricted local aid, according to administration officials.  The spending plan, the first in state history to exceed the $40 billion mark, relies on a forecast of $27 billion in tax collections next year.  Baker wrote in a message to lawmakers that his proposal “responsibly budgets for a $98 million deposit to the … (more)