ramsey: Nonlinear equations (3.2) from section 3.1 in HM(2009)
In common2016/HM2009: What the Package Does (One Line, Title Case)

we don't write a equation set, and get k through c, and it reduce the number of equation solved.

1	ramsey(k, k0, kT, alpha = 0.27, delta = 0.011, betax = 0.994, eta = 2)

`k`	a vector which length denotes the number of periods from `k0` to `kT`
`k0`	initial value for capital stock
`kT`	final value for capital stock
`alpha`	a parameter for production function
`delta`	rate of depreciation
`betax`	discount rate for unitity function
`eta`	a parameter for unitity funciton with flexible labor supply