[BUG] Tabulation causing error on parse_file

[felipemarkson]

Describe the bug
The character UTF-8 0x09 (Tabulation) is not recognized in the parse_file using .dss files.

Minimum Viable Example

DSS Code

// test.dss
Clear
new	circuit.test	bus1=SOURCEBUS	pu=1.0
New	Line.Line_1	bus1=SOURCEBUS	bus2=BUS_1
New	Load.Load_1	phases=3	conn=Wye	bus1=BUS_1	kw=0.1	kvar=0.03	model=1
solve

Julia File

import PowerModelsDistribution
const PMD = PowerModelsDistribution

case_file = "test.dss"

model_dict = PMD.parse_file(case_file)

Screenshots

System Information (please complete the following information):

• OS: Manjaro Linux x86_64
• Version Kernel Linux 5.15.60-1-MANJARO

[felipemarkson]

I think that the problem is this function:

PowerModelsDistribution.jl/src/io/dss/dss_parse.jl

Line 538 in 7a6b03e

function _parse_properties(properties::AbstractString)::Vector{String}

Because many of the validation statements use space. E.g.:

PowerModelsDistribution.jl/src/io/dss/dss_parse.jl

Lines 554 to 560 in 7a6b03e

	elseif !occursin("=", string_out) && (char == ' ' || n == num_chars)
	end_equality = true
	elseif occursin("=", string_out) && (char == ' ' || n == num_chars) && end_array
	end_equality = true
	else
	end_equality = false
	end

Maybe changing the space validation to the built-in Julia's function isspace can solve this issue.

@pseudocubic, I can create a PR if you are ok with this solution.

[pseudocubic]

@felipemarkson isspace looks like a promising solution, I would welcome the PR