Adding data_info parameter and stop messages

[mmc00]

Adding a parameter data_info where to write the coefficient and the description of real type data, and the description of the types of characters and integers. Also adding stop messages when the length of the header, coefficient and description is greater than required.

Example:

data = list(
REAL = array(
c(1, 2, 3, 4, 5, 6),
dim = c(2, 3),
dimnames = list(
dim1name = c('a', 'b'),
dim2name = c('f', 'g', 'h')
)
),
INTG = array(c(1L, 2L, 3L, 4L, 5L, 6L),
dim = c(2, 3)),
STRG =
c("STRING1", "STRING2", "STRING3")

)
data_extra = list(
REAL = c("REALD", "Real data type proof")
)
write_har(data, data_info = data_extra, 'test.har')