Return id of new characters (#21)

The long term plan is for these to return actual GenericCharacter
objects that are not part of the table, but rather reference the
table. But for now at least having the id of the new characters
make it possible to use these functions non-interactively

src/ModifyTable.jl

@@ -12,6 +12,7 @@ Append the tensor product of the character types `char1` and `char2` to the tabl
 julia> g=genchartab(\"GL2\");
 
 julia> tensor!(g,1,2)
+5
 
 julia> printinfochar(g,5)
 5	Any[\"Tensor of type 1 and 2\"]
@@ -34,7 +35,7 @@ function tensor!(t::CharTable{T}, char1::Int64, char2::Int64) where T <: NfPoly
 	param1 = shift_char_parameters(t, t.charparams[char1], 4)
 	param2 = shift_char_parameters(t, t.charparams[char2], 5)
 	push!(t.charparams, Parameters(vcat(param1.params, param2.params), vcat(param1.exceptions, param2.exceptions), ParameterSubstitution{T}[]))
-	return nothing
+	return length(t.charinfo)
 end
 function tensor!(t::SimpleCharTable{T}, char1::Int64, char2::Int64) where T <: NfPoly
 	if any((char1, char2).>chartypes(t))
@@ -47,7 +48,7 @@ function tensor!(t::SimpleCharTable{T}, char1::Int64, char2::Int64) where T <: N
 	end
 	push!(t.table, new_char)
 	push!(t.charinfo, ["Tensor of type $char1 and $char2"])
-	return nothing
+	return length(t.charinfo)
 end
 
 """
@@ -60,6 +61,7 @@ Append the (generic) central character of the character type `char` to the table
 julia> g=genchartab(\"GL2\");
 
 julia> omega!(g,1)
+5
 
 julia> printinfochar(g,5)
 5	Any[\"Omega of type 1\"]
@@ -78,7 +80,7 @@ function omega!(t::CharTable{T}, char::Int64) where T <: NfPoly
 	push!(t.table, new_char)
 	push!(t.charinfo, ["Omega of type $char"])
 	push!(t.charparams, t.charparams[char])
-	return nothing
+	return length(t.charinfo)
 end
 function omega!(t::SimpleCharTable{T}, char::Int64) where T <: NfPoly  # TODO is correct?
 	if char > chartypes(t)
@@ -91,7 +93,7 @@ function omega!(t::SimpleCharTable{T}, char::Int64) where T <: NfPoly  # TODO is
 	end
 	push!(t.table, new_char)
 	push!(t.charinfo, ["Omega of type $char"])
-	return nothing
+	return length(t.charinfo)
 end
 
 """
@@ -104,6 +106,7 @@ Append the linear combination of the character types `chars` with coefficients `
 julia> g=genchartab(\"GL2\");
 
 julia> lincomb!(g,[5,1],[1,2])
+5
 
 julia> printinfochar(g,5)
 5	Any[\"Lincomb 5 * type 1 + 1 * type 2\"]
@@ -145,7 +148,7 @@ function lincomb!(t::CharTable{T}, coeffs::Vector{Int64}, chars::Vector{Int64})
 		params[i]=shift_char_parameters(t, t.charparams[chars[i]], 5+i)
 	end
 	push!(t.charparams, Parameters(vcat(map(x -> x.params, params)...), vcat(map(x -> x.exceptions, params)...), ParameterSubstitution{T}[]))
-	return nothing
+	return length(t.charinfo)
 end
 function lincomb!(t::SimpleCharTable{T}, coeffs::Vector{Int64}, chars::Vector{Int64}) where T <: NfPoly
 	if length(coeffs)!=length(chars)
@@ -165,7 +168,7 @@ function lincomb!(t::SimpleCharTable{T}, coeffs::Vector{Int64}, chars::Vector{In
 	push!(t.table, new_char)
 	info=join(map(x -> join(x, " * type "), zip(coeffs, chars)), " + ")  # TODO
 	push!(t.charinfo, ["Lincomb $info"])
-	return nothing
+	return length(t.charinfo)
 end
 
 """