Aqua test failures

[ReubenJ]

Aqua picked up type piracies, undefined exports, and missing compat bounds in HerbGrammar. They are all related to types defined in HerbCore. The pirated methods should be moved to HerbCore, the exports removed, and compat bounds added.

Type Piracies Detected

Possible type-piracy detected:
[1] Dict{Symbol, Any}(grammar::AbstractGrammar) @ HerbGrammar HerbGrammar.jl/src/utils.jl:56
[2] Dict{Symbol, Any}(grammar::AbstractGrammar, mod::Module) @ HerbGrammar HerbGrammar.jl/src/utils.jl:56
[3] RuleNode(ind::Int64, grammar::AbstractGrammar) @ HerbGrammar HerbGrammar.jl/src/rulenode_operators.jl:1
[4] RuleNode(ind::Int64, _val, grammar::AbstractGrammar) @ HerbGrammar HerbGrammar.jl/src/rulenode_operators.jl:2
[5] UniformHole(domain::BitVector, grammar::AbstractGrammar) @ HerbGrammar HerbGrammar.jl/src/rulenode_operators.jl:4
[6] children(node::RuleNode) @ HerbGrammar HerbGrammar.jl/src/utils.jl:2
[7] display(rulenode::RuleNode, grammar::AbstractGrammar) @ HerbGrammar HerbGrammar.jl/src/rulenode_operators.jl:348
[8] getindex(grammar::AbstractGrammar, typ::Symbol) @ HerbGrammar HerbGrammar.jl/src/grammar_base.jl:48
[9] printnode(io::IO, node::RuleNode) @ HerbGrammar HerbGrammar.jl/src/utils.jl:3
[10] show(io::IO, grammar::AbstractGrammar) @ HerbGrammar HerbGrammar.jl/src/grammar_base.jl:186

Details

Undefined exports detected:
3-element Vector{Symbol}:
 Symbol("HerbGrammar.ContextFree")
 Symbol("HerbGrammar.ContextSensitive")
 Symbol("HerbGrammar.change_expr")

Missing Compat Entries

Base.PkgId(Base.UUID("4ef9e186-2fe5-4b24-8de7-9f7291f24af7"), "HerbGrammar") does not declare a compat entry for the following deps:
1-element Vector{Base.PkgId}:
 Serialization [9e88b42a-f829-5b0c-bbe9-9e923198166b]